7 lines (6 with data), 250 Bytes

e121a 0 128 0 15:15:00 01/03/1988
# Start time=15:15
# First beat=15:16:18.039
# <age-range>: 65-69, <sex>: Female, <medication>: None
# <RR-low-limit(sec)>: 0.414,  <RR-high-limit(sec)>: 1
# Note: recording with a timing signal, flutter-compensated